/**
 * ALTWIND.c -- Sine Wave Using PolyLine
 *              (c) Charles Petzold, 1998
 */
#include <windows.h>
#include <math.h>

#define NUM     10000
#define TWOPI   6.283185307

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("AltWind");
    HWND hwnd;
    MSG msg;
    WNDCLASS wndclass;

    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;

    if (!RegisterClass(&wndclass)) {
        MessageBox(NULL, TEXT("This program requires Windows NT!"), szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName,
                        TEXT("Alternate and Winding Fill Modes"),
                        WS_OVERLAPPEDWINDOW,
                        CW_USEDEFAULT, CW_USEDEFAULT,
                        CW_USEDEFAULT, CW_USEDEFAULT,
                        NULL, NULL, hInstance, NULL);
    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static POINT aptFigure[10] = {  10, 70, 50, 70, 50, 10, 90, 10, 90, 50,
                                    30, 50, 30, 90, 70, 90, 70, 30, 10, 30};
    static int cxClient, cyClient;
    HDC hdc;
    int i;
    PAINTSTRUCT ps;
    POINT apt[10];

    switch (message)
    {
        case WM_CREATE:
            hdc = GetDC(hwnd);
            ReleaseDC(hwnd, hdc);
            
            return 0;
        case WM_PAINT:
            hdc = BeginPaint(hwnd, &ps);
            SelectObject(hdc, GetStockObject(GRAY_BRUSH));
            for (i=0; i<10; i++) {
                apt[i].x = cxClient * aptFigure[i].x/200;
                apt[i].y = cyClient * aptFigure[i].y/100;
            }
            SetPolyFillMode(hdc, ALTERNATE);
            
            Polygon(hdc, apt, 10);
            for (i=0; i<10; i++) {
                apt[i].x += cxClient / 2;
            }
            SetPolyFillMode(hdc, WINDING);
            Polygon(hdc, apt, 10);
            
            EndPaint(hwnd, &ps);
            return 0;
        case WM_SIZE:
            cxClient = LOWORD(lParam);
            cyClient = HIWORD(lParam);
            return 0;
        case WM_DESTROY:
            PostQuitMessage(0);
            return 0;

        default: break;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}